#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "sdkconfig.h"
#include "lwip/err.h"
#include "lwip/sys.h"

#include "wifi_station.h"



/* The examples use WiFi configuration that you can set via project configuration menu

   If you'd rather not, just change the below entries to strings with
   the config you want - ie #define EXAMPLE_WIFI_SSID "mywifissid"
*/
#define EXAMPLE_ESP_WIFI_SSID      CONFIG_EXAMPLE_WIFI_SSID
#define EXAMPLE_ESP_WIFI_PASS      CONFIG_EXAMPLE_WIFI_PASSWORD
#define EXAMPLE_ESP_MAXIMUM_RETRY  5

/* FreeRTOS event group to signal when we are connected*/
static EventGroupHandle_t s_wifi_event_group;

/* The event group allows multiple bits for each event, but we only care about two events:
 * - we are connected to the AP with an IP
 * - we failed to connect after the maximum amount of retries */
#define WIFI_CONNECTED_BIT BIT0
#define WIFI_FAIL_BIT      BIT1

static const char *TAG = "wifi station";

static int s_retry_num = 0;

//事件处理回调函数
static void event_handler(void* arg, esp_event_base_t event_base,int32_t event_id, void* event_data)
{
    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) 
	{
		ESP_LOGI(TAG, ">>> wifi station start >>>");
        esp_wifi_connect();
    } 
	else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) 
	{
        if (s_retry_num < EXAMPLE_ESP_MAXIMUM_RETRY) 
		{
            esp_wifi_connect();
            s_retry_num++;
            ESP_LOGI(TAG, "retry to connect to the AP");
        } 
		else
		{
            xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
        }
        ESP_LOGI(TAG,"connect to the AP fail");
    } 
	else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) 
	{
        ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
        ESP_LOGI(TAG, "got ip:" IPSTR, IP2STR(&event->ip_info.ip));
        s_retry_num = 0;
        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
    }
}

void wifi_init_sta(void)
{
    s_wifi_event_group = xEventGroupCreate();    //创建一个事件标志组

    ESP_ERROR_CHECK(esp_netif_init());    //初始化网络协议栈相关接口

    ESP_ERROR_CHECK(esp_event_loop_create_default());   //设置默认的事件循环
    esp_netif_create_default_wifi_sta();    //创建一个默认的STA站点

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();   //设置默认的WiFi参数
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));    //初始化WiFi模块

    esp_event_handler_instance_t instance_any_id;
    esp_event_handler_instance_t instance_got_ip;

	//注册WIFI_EVENT，事件的回调函数是 event_handler
    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,ESP_EVENT_ANY_ID,&event_handler,NULL,&instance_any_id));
	//注册IP_EVENT，事件的回调函数是 event_handler
    ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT,IP_EVENT_STA_GOT_IP,&event_handler,NULL,&instance_got_ip));

	//WiFi参数，包含要连接的SSID和密码
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = EXAMPLE_ESP_WIFI_SSID,
            .password = EXAMPLE_ESP_WIFI_PASS,
            /* Setting a password implies station will connect to all security modes including WEP/WPA.
             * However these modes are deprecated and not advisable to be used. Incase your Access point
             * doesn't support WPA2, these mode can be enabled by commenting below line */
	     .threshold.authmode = WIFI_AUTH_WPA2_PSK,

            .pmf_cfg = {
                .capable = true,
                .required = false
            },
        },
    };
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA) );    //初始化为WIFI STA模式
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config) );  //设置STA模式下的参数
    ESP_ERROR_CHECK(esp_wifi_start() );   //启动WIFI

    ESP_LOGI(TAG, "wifi_init_sta finished.");

    /* Waiting until either the connection is established (WIFI_CONNECTED_BIT) or connection failed for the maximum
     * number of re-tries (WIFI_FAIL_BIT). The bits are set by event_handler() (see above) */
	//等待事件标志组的置位
    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
            WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
            pdFALSE,
            pdFALSE,
            portMAX_DELAY);

    /* xEventGroupWaitBits() returns the bits before the call returned, hence we can test which event actually
     * happened. */
    if (bits & WIFI_CONNECTED_BIT) 
	{
        ESP_LOGI(TAG, "connected to ap SSID:%s password:%s",EXAMPLE_ESP_WIFI_SSID, EXAMPLE_ESP_WIFI_PASS);
    } 
	else if (bits & WIFI_FAIL_BIT) 
	{
        ESP_LOGI(TAG, "Failed to connect to SSID:%s, password:%s", EXAMPLE_ESP_WIFI_SSID, EXAMPLE_ESP_WIFI_PASS);
    } 
	else 
	{
        ESP_LOGE(TAG, "UNEXPECTED EVENT");
    }

    /* The event will not be processed after unregister */
    ESP_ERROR_CHECK(esp_event_handler_instance_unregister(IP_EVENT, IP_EVENT_STA_GOT_IP, instance_got_ip));
    ESP_ERROR_CHECK(esp_event_handler_instance_unregister(WIFI_EVENT, ESP_EVENT_ANY_ID, instance_any_id));
    vEventGroupDelete(s_wifi_event_group);
}


